This invention relates to improvements in plural image cameras of the type having facilities for superimposing on a common film portion noncoincident imaging light beams from an external object and from a separately illuminable item such as an internal transparency. Examples of such arrangements are shown, e.g., in U.S. Pat. No. 3,111,887, issued to W. G. Alexander on Nov. 26, 1963; U.S. Pat. No. 3,376,800, issued to W. Faasch on Apr. 9, 1968; and U.S. Pat. No. 3,495,267, issued to I. Brodie on Feb. 10, 1970.
Multi-image arrangements of this type have in the past employed certain limited adjustments of the quantity of light incident on the camera film. Such adjustments, however, generally have been restricted to still-camera applications and have normally required the manual variation of the transparency illumination after a subjective inspection of the composite images on the film by an observer with the aid of a view finder. Certain of these arrangements, exemplified by the above-mentioned U.S. Pat. Nos. 3,376,800 and 3,495,267, employ known beam-splitting techniques to permit the viewing of the superimposed images prior to exposure.
Such limited manual exposure adjustments are slow and cumbersome even for still camera applications, and are completely impractical for moving picture camera applications.
An object of the present invention, therefore, is to provide an improved multi-image camera having facilities for rapidly and automatically adjusting the exposure of a composite image directed at the camera film.
A related object is to provide facilities for incorporating improved automatic exposure control in a moving picture camera of the multi-image type.